Metal Salts of 4,5‐Dinitro‐1,3‐imidazole as Colorants in Pyrotechnic Compositions

Abstract

Abstract4,5‐Dinitroimidazole (1) (4,5‐DNI) was synthesized by nitration of commercially available 4‐nitro‐imidazole. Several alkaline and alkaline earth metal salts of 4,5‐dinitro‐1,3‐imidazole were synthesized by reaction of DNI with stoichiometric amounts of the corresponding metal hydroxides and carbonates. The synthesized salts, LiDNI·3H2O (2), NaDNI·H2O (3), KDNI·H2O (4), Ca(DNI)2·5H2O (5), Sr(DNI)2·3H2O (6), and Ba(DNI)2·4H2O (7) were characterized comprehensively by means of single‐crystal X‐ray diffraction, NMR and vibrational (IR/Raman) spectroscopy, mass spectrometry, elemental analysis, and differential scanning calorimetry (DSC). A detailed description of their potential use as flame colorants in pyrotechnical compositions is also given. Their color properties regarding the dominant wavelength, spectral purity, luminous intensity and luminous efficiency were measured. Last but not least the investigated salts were found to be insensitive in terms of friction and impact tested with BAM methods.